Cachexia (extreme malnutrition with associated muscle wasting) is found in nearly 40% of patients hospitalized with cancer and is the most common cause of death in patients with malignancy. Operative resection of tumor is often the primary or first line treatment of cancer. There is evidence that intravenous nutritional repletion prior to surgery may decrease surgical morbidity and mortality. An easily performed and sensitive test which can identify precise early improvement in nutritional status is critical. This project is a short term, preliminary study whose purpose is to assess the utility of magnetic resonance spectroscopy as a probe to measure nutritional depletion and the response to repletion on a cellular/tissue level using a defined intravenous nutritional protocol (parenteral nutrition or PN.) Both acutely and chronically malnourished patients develop abnormal muscle function when evaluated by standardized stimulatory muscle function tests. This muscle abnormality may contribute significantly to the high risk of surgical morbidity. The non-invasive, non-destructive nature of in vivo NMR spectroscopy and its compatibility with tests of muscle function makes it an ideal method for this purpose. Serial examinations of malnourished patients will be performed before and during repletion using NMR as well as biochemical, bioelectrical, and functional evaluation. Careful investigation of possible correlates between the spectral data and clinical and functional measures of nutritional status will determine whether magnetic resonance spectroscopy yields a useful, non-invasive assessment of response to nutritional therapy in the individual patient.